I bought a wolverine that supposedly just needed carb work. The bike will idle but as soon as you give it gas it sputters and backfires out of the carb usually stalling. The previous owner i noticed had a 185 main jet in it (seemed odd), so i bought the original 145 jet and it pretty much runs the exact same. Runs better with the choke on.. if you ease into the throttle you can pin it.. though it has no power and tops out at like 15mph. Cleaned the carb a million times, tried a chinese carb, adjusted the needle to every position, ran from a second fuel tank, replaced intake boot, adjusted valves, compression 120psi... parking brake is disconnected so its not that. Somewhat new to this but im stumped.

 

First fit a new plug and check inlet manifold for cracks and leaks. Next check valve timing. If timing is out, check piston is at TDC when the timing mark says it is (difficult I know, to be certain, within a few degrees, by watching piston through plug hole).

It may be an electrical problem, but finding out if it is coil, stator or CDI, winds up expensive if you go down the substitution route, and the fact it runs means any ignition tests in the workshop manual will probably show it as being OK.

I did once have an Eiger that did this and it turned out to be a plugged exhaust, why and how, I have no idea, though it had stood outside unused, for over a year, removing the silencer instantly cured it.

 

I have had alot of them that had clutch and brake switch at handlebar be bad we bypass them one at a time to find the issue

 

Thanks for the pointers i actually did a vin check and it's a 1999 not a 2001.. so PO was wrong. Im positive it doesnt have an intake leak nor parking brake issue. The other switch for the clutch/brake works properly.. i can hear the relay click when i pull the lever and it starts up fine. Im kind of all over the place atm but i took apart my carb and noticed that the float isnt parallel with the carb body in the bowl but parallel to the diaphram/jets...tho other carb i have the float is parallel with the slanted carb body. Im going to set it level to the body and see if it makes a difference. In the meantime i took the crankcase cover off to look at the stater. I did an ohm test on the two pickup coils (there are two on this year apparently). One came back 300 ohms and the other came back with no reading.. stays .1 on my multimeter.

 

Getting info on the pickup coils is proving difficult. All the info i can find is for the single coil models. Both coils seem to be powered by the same white/red wire which is spliced together before it meets the harness plug.. then there's a blue wire from one coil and a white/green from the other. 300 ohms white/green to white/red but none from white/red to blue. Am i staring my problem right in the face? Either way, definitely learning something.

Think im gonna order a coil and splice it in. Not sure what the exact ohms should be on the coils but considering they're both labeled with the same part number i see no reason one shouldn't have a reading.

 

Yes, you would expect the same reading for both coils. Wonder why Yamaha fitted two, anyone know, or how it works? As it is going to produce a pulse 180 degrees out, near bottom dead centre, on the second coil.